New Jersey State Police have issued a carjacking alert for the Newark area after two cars, both Mercedes Benzes, were stolen in four days after being "bumped" from behind on Route 78.

In both cases, a 2013 Mercedes was struck from behind. When the drivers got out to inspect the damage, a second person from the other car jumped into the passengers seat of the victim's car and then both cars sped away, leaving the victim standing in the road.

The first bump-and-run theft happened on Tuesday at 10:45 a.m. when the luxury car was struck by a Chevy. The victim told police that both cars drove off and exited Route 78 at Exit 56, which goes to Newark.

The second carjacking happened at 6:20 a.m. on Friday when Mercedes CLS was bumped from behind by black Audi sedan.  When the victim went to the shoulder of the road to inspect the damage, two suspects exited the Audi and one jumped into the driver's seat.  When the victim tried to stop him, a third accomplice exited the Audi and charged at him.  The victim stopped struggling and both cars took off. 

Police ask anyone with information on these crimes to call the Somerville State Police Station at 908-725-0107.  Police also caution motorists who are struck from behind to "to think carefully about their response and take appropriate actions to maintain their safety."  Police offered this guidance:

• First, never stop your vehicle in the traveled part of the road unless it is disabled
   
• Next, call 911 to report the crash
   
• Look for signage to identify your location to police dispatchers. Especially useful are those green milepost markers that are placed every 1/10th mile on many highways.
   
• If you’re concerned that a minor crash may have been intentional, lock your doors and roll up your windows until police arrive. If your safety is still jeopardized, move your vehicle to a safer place and advise police of your location.